Critical fire conditions are expected in central and southeastern Montana where wildfires are already burning hundreds of square miles.
The National Weather Service says temperatures could reach up to 105 degrees in the region Tuesday, with low humidity and wind gusts up to 30 mph.
Those conditions could present a problem for firefighters battling the erratic Ash Creek Fire, which has jumped U.S. Highway 212 and triggered evacuations between Broadus and Ashland.
Officials estimated the 186,800-acre fire was 55 percent contained. The fire had burned 16 residences and 22 outbuildings burned as of Monday.
Authorities say the 22,000-acre Dahl fire in Musselshell County is 95 percent contained after burning 73 homes and 150 other buildings.
The weather service says red-flag conditions are also expected for southwestern Montana.